Without limiting the scope of the invention, its background is described in connection with Filovirus infection of small mammals.
Volchkov, et al., in an article entitled “Molecular Characterization of Guinea Pig-Adapted Variants of Ebola Virus,” Virology 277, 147±155 (2000), 147-155, teach that serial passage of initially nonlethal Ebola virus (EBOV) in outbred guinea pigs resulted in the selection of variants with high pathogenicity. It was further found by nucleotide sequence analysis of the complete genome of the guinea pig-adapted variant 8mc, that the guinea pig-adapted variant differed from wild-type virus by eight mutations, however, no mutations were identified in nontranscribed regions, including leader, trailer, and intragenic sequences.
Mateo, et al., in an article entitled “VP24 Is a Molecular Determinant of Ebola Virus Virulence in Guinea Pigs,” J. Inf. Dis. 2011:204 (Suppl. 3), S1011-S1020, show that serial passaging of EBOV in guinea pigs results in a selection of variants with high pathogenicity. They teach, using a reverse genetics approach, that the increase in EBOV pathogenicity is associated with amino acid substitutions in the structural protein VP24, however, replication of recombinant EBOV carrying wild-type VP24 was impaired in primary peritoneal guinea pig macrophages and in the liver of infected animals. The substitutions in VP24 allowed EBOV to replicate in guinea pig macrophages and spread in the liver of infected animals.
Subbotina, et al., in an article entitled “Genetic factors of Ebola virus virulence in guinea pigs,” Virus Research 153 (2010) 121-133, teach that selective passages of Ebola virus in guinea pigs resulted in a guinea pig-adapted strain (GPA-P7) strain. By the 7th passage, the infection with the adapted EBOV induced a lethal disease in animals accompanied by the characteristic hematological changes, viz., leukocytosis (primarily due to neutrophilia), a pronounced deficiencies in platelets, lymphocytes, monocytes and a significant decrease of blood neutrophil's phagocytic capacity. The increased virulence is said to correlate with appearance of several nucleotide substitutions: in the genes NP, A2166G (N566S), VP24, U10784C (L147P), G10557A (M711), G10805U (R154L), and L, G12286A (V2361). It was theoretically calculated that the mutations associated with an increase in EBOV virulence alter the secondary structure of the proteins NP (C-terminal region) and full-sized VP24.